Thanks for adding the extra pictures, Dave, but it hasn't really helped much! The images are rather dark but even some tweaking in Photoshop doesn't help very much. I presume that this is not a final instar larva (caterpillars can change in appearance quite a lot from one instar to the next, so knowing the size might have helped a little bit). My best guess is still Dark Dagger but it doesn't look quite right to me so don't take that as a firm ID.

The fly mine on birch looks dipterous so could well be Agromyza alnibetulae. I take it that you will already have checked here: http://www.leafmines.co.uk/html/Plants/betula.htm . This web-site (and the Dutch equivalent at http://www.bladmineerders.nl/) is well worth looking at before asking questions about leaf-mines, especially as "high season" for them is only a month or so away now!

Looks like one of the footman to me. First thought was Red-necked for which the markings fit but the colour is different - might be the yellow form. Keep it and rear it. I found a RNF larvae in my trap last year and reared it through very easily. BW, Marc

Marc, I don't have the caterpillar I'm afraid. I have had RNF caterpillars on the burial park trap before, although it didn't look the same as those.

Dave, it's always very dark in those woods and I was in a hurry to get to an appointment! I do look at the leafmines and flymines websites, but so many of these things look the same to me! There are a few I can do OK now, especially after going out with Mr King around the COAM site. I think I'd do well to attend Mr Fletcher's Leaf Mines day in the BIG calendar...